Buffered Video Recording for Video Cameras

ABSTRACT

A battery-powered camera includes a system processor configured to operate in a standby mode or a full-power mode. While operating the system processor in the standby mode, the camera detects an event in a field of view of the camera; records, using an image sensor of the camera, a plurality of image frames corresponding to the field of view in which the event was detected; stores in a frame buffer the plurality of image frames; and wakes the system processor from the standby mode. While operating the system processor in the full-power mode, the camera processes the plurality of image frames stored in the frame buffer using the system processor; and provides the processed image frames for streaming.

RELATED APPLICATION(S)

This application is a continuation of and claims priority to U.S. patentapplication Ser. No. 17/149,569, filed on Jan. 14, 2021, the disclosureof which is incorporated by reference herein in its entirety.

TECHNICAL FIELD

This relates generally to event-based video recording at a cameradevice, including but not limited to buffering video data while variousprocessing components of a camera device power on after an eventdetection.

BACKGROUND

Video surveillance systems that use battery-powered cameras are subjectto trade-offs in power consumption versus functionality. A system thatprovides a continuous stream of video data may require a level of powerconsumption that prohibits the use of battery-powered devices. Suchsystems may be referred to as continuous video recording (CVR) systems.On the other hand, a system that limits the recording of video data tovideo clips associated with detections of particular events (e.g.,motion or audio events) may require less power and is better suited tobattery-powered implementations. Such systems may be referred to asevent-based recording (EBR) systems.

EBR systems may save power by keeping high-power recording and/orprocessing components in low-power state until an event is detected.Upon detection of an event, however, recording and/or processing delaysmay result from the amount of time it takes these components to bepowered up. As a result, important activity (e.g., the activity thatcaused the system to detect the event) may be missing from the videoclip associated with the event.

SUMMARY

This disclosure describes a buffered video recording (BVR) system thatuses a fast-boot image sensor with on-chip motion detection to quicklycapture and buffer video data while a system processor is in the processof transitioning out of a standby mode. When the system processor haspowered on and image processing software has initialized, the bufferedvideo data is transferred for processing and streaming. As a result ofquicker video capture and pre-processor buffering, a battery-poweredcamera implementing a BVR system may remain in a low-power state betweenevent detections while providing video clips associated with detectedevents that are less likely to miss important activity.

In one aspect, some implementations include a battery-powered cameradevice and/or a method performed at a battery-powered camera device. Thebattery-powered has a system processor that is configured to operate ina standby mode or a full-power mode. Prior to operating the systemprocessor in the full-power mode, the camera device (i) detects motionin a field of view of the camera; (ii) records, using the image sensor,a plurality of image frames corresponding to the field of view in whichthe motion was detected; (iii) buffers the plurality of image frames;and (iv) transitions the system processor from the standby mode to thefull-power mode. Subsequent to transitioning the system processor to thefull-power mode, the camera device uses the system processor to processthe buffered plurality of image frames, and provides the processed imageframes for streaming.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the various described implementations,reference should be made to the Detailed Description below, inconjunction with the following drawings in which like reference numeralsrefer to corresponding parts throughout the figures.

FIGS. 1A-1B are block diagrams of an event detection system implementinga BVR technique in accordance with some implementations.

FIG. 2 is a table of BVR operation modes in accordance with someimplementations.

FIG. 3 is a diagram of an event detection scenario in accordance withsome implementations.

FIG. 4 is a diagram of an event detection scenario implementing a BVRtechnique in accordance with some implementations.

FIG. 5 is a flow diagram of an event detection process implementing aBVR technique in accordance with some implementations.

DETAILED DESCRIPTION

FIGS. 1A-1B are block diagrams of an event detection system 100 inaccordance with some implementations. Referring to FIG. 1A, the eventdetection system 100 includes a camera device 102, communicationnetwork(s) 120, a server system 130, and/or a mobile device 140. Inother implementations, there may be a plurality of server systems 130,no server system 130, a plurality of mobile devices 140, no mobiledevice 140, and/or no communication network(s) 120. For example, thecamera device 102 may wirelessly stream video data to a server system130 for storage or additional processing, and a user may access thevideo data using a mobile device 140 in communication with the serversystem 130. Alternatively, the camera device 102 may wirelessly streamvideo data to a mobile device 140. Alternatively, the camera device 102may store video data locally without streaming it, making the video dataavailable for retrieval at the camera device itself Regardless of theimplementation, the event detection system 100 includes at least animage sensor 112 having a field of view (FOV) 113 extending from thecamera device 102, a frame manager 107, a system processor 108configured to run image processing software (SW) 109, communicationcircuitry 110, memory 106, and a power source, such as a battery 104. Insome implementations, the camera device 102 includes, or is locallynetworked with, event detection circuitry 114 (e.g., a motion sensorand/or an audio sensor).

To maximize battery life, one or more of the aforementioned componentsof the camera device 102 may operate in a low-power mode or state (alsoreferred to as standby, sleep, power-saving, or disabled). Specifically,a component operating in a low-power mode may require an amount of powersuch that the component can function for a period of time (e.g., atleast a day, a week, a month, or longer) on power provided by thebattery 104 without depleting the battery's power reserve to a levelthat compromises other functions of the camera device 102 that also relyon power provided by the battery 104. As a non-limiting example, somelow-power motion sensors (e.g., passive infrared (PIR) sensors) may drawonly several milliwatts of power (e.g., up to 10 milliwatts).

In contrast, a component may operate in a high-power mode or state (alsoreferred to as full power, wake, or enabled). Specifically, a componentoperating in a high-power mode may require an amount of power such thatthe component's power requirements would deplete the battery 104's powerreserve in a relatively short amount of time (e.g., less than an hour,less than a day, or less than a week). As a non-limiting example,pixel-based image processing using an image sensor may draw multiplewatts of power (e.g., 5 watts). Such a power draw could deplete thebattery in a battery-powered camera within hours.

While some components of the camera device 102 may be designed orotherwise configured to operate only in a low-power mode (e.g., a motionsensor included in event detection circuitry 114), other components ofthe camera device 102 may be designed or otherwise configured to switchbetween low-power and high-power modes (e.g., the image sensor 112and/or the system processor 108). In the latter case, such a componentcould remain in a low-power mode while the component (or a functionprovided by the component) is either not being used or does not requirefull power. Such a component could transition to a high-power mode whenthe component (or a function provided by the component) is required toexecute a function of the camera device 102 requiring full power. Such acomponent may take a nonzero amount of time to transition from thelow-power mode to the high-power mode. This amount of time may bereferred to herein as a delay or a latency (e.g., a transition delay, awake delay, or a processing delay).

The system processor 108 includes one or more processors or processingcores for executing programs stored in the memory 106. In someimplementations, the system processor 108 is a system on a chip (SoC),which integrates a plurality of processing functions of the cameradevice 102 (e.g., including image processing, object detection andrecognition, communications, system diagnostics, power regulation,day/night mode adjustments, and so forth). The system processor 108 maycomprise an image processor, with other processing functions beinghandled by other processing components of the camera device 102. In someimplementations, the system processor 108 may function in a high-powermode or a low-power mode. Specifically, when high-power functions arenot required or not being used, the system processor 108 may be disabledor kept in a low-power standby state until such high-power functions areneeded.

The memory 106 stores programs that, when executed by elements of thesystem processor 108, perform one or more of the functions describedbelow. In some implementations, the memory 106 may be partially orcompletely implemented or otherwise included in the system processor108. The memory 106 may include high-speed random access memory, such asDRAM, SRAM, DDR RAM, or other random access solid state memory devices.The memory 106 may include non-volatile memory, such as one or moremagnetic disk storage devices, one or more optical disk storage devices,one or more flash memory devices, or one or more other non-volatilesolid state storage devices. The memory 106 may include one or morestorage devices remotely located from one or more processing units ofthe system processor 108.

The image processing software 109 (alternatively referred to as an imageprocessing module) may be configured to execute image processingfunctions on image data recorded by the image sensor 112. Example imageprocessing functions include white balance adjustments, object detectionand/or recognition, facial detection and/or recognition, image-basedday/night mode adjustment determinations, and event notificationthreshold determinations (e.g., determining whether an event of interestrecorded in the field of view 113 satisfies one or more thresholdsrequired for causing the camera device 102 to (i) continue recording theevent and/or (ii) transmit a notification and/or video data using thecommunication circuitry 110 to a user). Specifically, if the imageprocessing software 109 detects and/or recognizes a person or object ofinterest in the field of view 113, the camera device 102 may continue torecord video data captured by the image sensor 112, store the video dataas an event (a video clip associated with an event), and/or upload thevideo data to a server system 130 or a mobile device 140 as an event.The recording of video data based on motion detection, personrecognition, and/or object recognition is referred to herein asevent-based recording. In some implementations, the system processor 108must be in a full-power state and the image processing software 109 mustbe initialized in order to execute one or more of the aforementionedimage processing functions. In some implementations, the imageprocessing software 109 uses one or more machine learning algorithms toperform one or more of the aforementioned image processing functions.

The image sensor 112 may be configured to operate in one of a low-powermotion detection mode and a high-power image capture mode (also referredto as an image recording mode or an image sensing mode). To support thelow-power motion detection mode, the image sensor 112 may be implementedwith on-chip motion detection functionality, which enables the imagesensor 112 to detect motion in the field of view 113 usinglow-resolution images captured by the image sensor 112. Low resolution,as disclosed herein, may comprise any resolution that is less than afull-resolution capability of the image sensor 112, as long as the imagesensor 112 can operate in a low-power mode while capturing such images.While in the low-power (low resolution) motion detection mode, the imagesensor 112 may be configured to transition to the high-power (fullresolution) image capture mode upon detection of motion in the field ofview 113. The transition delay may be configured to last on the order ofthe amount of time it takes for the image sensor 112 to capture a singlefull-resolution image (referred to as a fast-boot function). As such,upon transitioning to the high-power (full resolution) image capturemode, the image sensor 112 may immediately (or close to immediately)begin capturing full-resolution images of the activity that was thesubject of the detected motion.

The frame manager 107 is configured to store images captured by theimage sensor 112 until the images can be further processed and/oranalyzed by the image processing software 109 of the system processor108. In some implementations, the frame manager 107 includes afirst-in-first-out (FIFO) buffer. The frame manager 107 may be includedin the memory 106, or it may be implemented as a separate component ofthe camera device 102 including its own data storage hardware (e.g.,including a buffer). When the system processor 108 has completedtransitioning to a full-power state (has fully powered on) and the imageprocessing software 109 has initialized, the frame manager 107 maytransfer the stored images to the system processor 108 for furtherprocessing (e.g., white balance processing) and/or analysis (e.g.,object recognition).

The communication circuitry 110 is configured to transmit video data(e.g., images captured by the image sensor 112 and processed by thesystem processor 108) via the communication network(s) 120 to a serversystem 130 and/or a mobile device 140. This transmission process isreferred to herein as streaming. In some implementations, thecommunication circuitry must be operating in a high-power mode in orderto stream video data, and thus may be powered down when not in use ornot required. The communication network(s) 120 may include any wirelesswide area network (e.g., the Internet) and/or local area network (e.g.,Wi-Fi).

The camera device 102 optionally includes event detection circuitry 114including, for example, a motion sensor and/or an audio sensor. Suchsensor(s) may supplement or replace the low-power motion detection modeof the image sensor 112. Further, such sensor(s) may operate in alow-power mode so as to provide event detection capabilities whilehigh-power components of the camera device 102 are in a low-power state.For purposes of this disclosure, event detection may refer to detectionof any movement or sound corresponding to any activity in proximity tothe camera device 102 (regardless of whether the activity is in thefield of view 113).

Referring to FIG. 1B, data from image frames captured by the imagesensor 112 is conveyed along an image data bus to the frame manager 107and to the system processor 108. The image data bus may be any data buscapable of conveying image data at a bandwidth that can support fullresolution image capture by the image sensor 112 (e.g., using an imagetransfer protocol such as mobile image processing interface (MIPI)).When the on-chip motion detection feature of the image sensor 112detects an event, the image sensor 112 transitions to the high-power(full resolution) image capture mode and propagates an interrupt signal(also referred to as a control signal or a wake signal) to the framemanager 107 and the system processor 108. Alternatively, when the eventdetection circuitry 114 (e.g., a motion sensor) detects an event, theevent detection circuitry propagates the interrupt signal to the imagesensor 112, the frame manager 107, and the system processor 108. Uponreceiving the interrupt signal, each respective component wakes up orotherwise enables itself in order to operate in a high-power mode. Insome implementations, the image sensor 112, frame manager 107, andsystem processor 108 may communicate using a serial communication bus(e.g., I²C).

FIG. 2 is a table of BVR operation modes in accordance with someimplementations. When the camera device 102 is in a monitor operationmode 202, the image sensor 112 is in a low-power motion detection modeas described above, and the frame manager 107 and system processor 108are each in a low-power standby mode in order to conserve battery power.Upon detection of an event (e.g., a motion event), the camera device 102may switch to a buffer operation mode 204. In this mode, the imagesensor 112 switches to a high-power image capture mode in order torecord image data, the frame manager 107 switches to an active mode inorder to store the image data captured by the image sensor 112, and thesystem processor 108 begins to wake up (transition to a high-powermode). When the system processor 108 is fully awake (functioning in thehigh-power mode) and image processing software 109 is fully initialized,the camera device 102 may switch to a stream operation mode 206. In thismode, the image sensor 112 continues to record image data, the framemanager 107 continues to store the recorded image data, and the systemprocessor 108 processes the stored image data.

FIG. 3 is a diagram of an event detection scenario 300 in accordancewith some implementations. The event detection scenario 300 demonstratesthe relatively high amount of missing image data that may occur withoutthe use of the BVR techniques described herein. In the event detectionscenario 300, an event (e.g., motion) occurs at the beginning of timeinterval t₀, and the event detection circuitry 114 (e.g., a PIR motionsensor) detects the event after a delay t₀. The length of the delay t₀may depend on the capability of the event detection circuitry 114. Priorto detecting the event (e.g., prior to and during time period to), thesystem processor 108 and the image sensor 112 may be in a low-powerstandby mode. Upon detecting the event, the event detection circuitry114 communicates the detection (e.g., by sending a control signal) tothe system processor 108 at the beginning of time interval t₁. As aresult of the event detection, the processing circuitry 108 powers up(wakes up). This transition is associated with a delay of t₁, duringwhich the image sensor 112 remains powered down in a standby mode. Oncethe system processor 108 is powered up at the beginning of time intervalt₂, the system processor 108 causes the image sensor 112 to power up(wake up) to a full-power image capture mode. This power-up transitionis associated with a delay of t₂, during which the system processor 108is active but not processing image data (image frames) since the imagesensor 112 is still waking up. At the beginning of time interval 13, theimage sensor 112 begins capturing image frames, but these image framesare not processed by the system processor 108 because the imageprocessing software 109 is still initializing. The length of the imageprocessing software 109 initialization delay 13 may depend in part onthe amount of time it takes for the image processing software 109 todetermine imaging parameters (e.g., exposure and white balance) to beapplied at the image sensor 112 and/or to the image data captured by theimage sensor 112. Upon determining the imaging parameters, the imageprocessing software 109 causes the system processor 108 to apply theimaging parameters at the image sensor 112 and/or to the image datacaptured by the image sensor 112 at the beginning of time interval t₄,at which time the first valid frames may be recorded and provided forstreaming.

During the aforementioned wake-up and initialization delays (t₀-t₃),either no image frames are being recorded, or the image frames that arebeing recorded are not optimized for viewing (e.g., not captured withproper exposure or white balance settings). As such, these image framesare characterized as missing frames, and they are not included in avideo clip associated with the detected event. Stated another way, anyactivity that occurred in the field of view 113 during time intervalst₀-t₃ is not captured in a video clip corresponding to that activity.

FIG. 4 is a diagram of an event detection scenario 400 using a BVRtechnique in accordance with some implementations. The BVR techniqueminimizes the amount of missing frames by storing image frames in theframe manager 107 while the system processor 108 is waking up and theimage processing software 109 is initializing (during the bufferoperation mode 204). The frame manager 107 transfers the image framesfor processing once the system processor 108 is powered on and the imageprocessing software 109 is initialized (during the stream operation mode206).

Specifically, in the event detection scenario 400, an event (e.g.,motion) occurs at the beginning of time interval t₀ (while the cameradevice 102 is in the monitor operation mode 202). The event may bedetected by event detection circuitry 114 (not depicted) or by the imagesensor 112 while in a low-power (low resolution) motion detection mode(as depicted during time interval t₀ in FIG. 4 ). Upon detecting themotion event, the image sensor 112 transitions to a high-power (fullresolution) image capture mode during time interval t₁. During thetransition delay (depicted as “Del”) associated with this time interval,no image frames are captured. However, if the amount of time included intime intervals t₀ and t₁ is less than the amount of time it takes forthe image sensor 112 to capture an image frame, then there will be nomissing frames after detection of the event. As such, the first framesthat are initially captured at the beginning of time interval t₂ aremore likely (compared to the initial frames at 14 in scenario 300) tocapture the activity in the field of view 113 that is the subject of thedetected event. This initial activity (at the beginning of t₂) may bemore relevant to the event detected at to than subsequent activity, sothe ability to record image frames capturing this initial activity issignificant from a user's perspective. Stated another way, the captureof the event may appear to be instantaneous from the user's perspective,since the very first frame captured at the beginning of t₂ includesactivity that is similar to what the user would have seen without thedelay t₁.

The image frames captured beginning at interval t₂ (while the cameradevice 102 is in the buffer operation mode 204) are transmitted to theframe manager 107, which stores them until the system processor 108wakes up (t₃) and the image processing software 109 is initialized (t₄).Before time interval 12, the frame manager 107 and the system processor108 may be in a low-power state. Prior to and/or during the transitiondelay t₁, the image sensor 112 may configure (or tune or establish)exposure levels so that when the image sensor 112 begins capturing imageframes at the beginning of time interval t₂, the exposure levels mayalready be optimized, allowing the captured image frames to be optimizedfor viewing (subject to further processing) by a user.

Upon transitioning to the high-power image capture state at thebeginning of time interval 12, the image sensor 112 (or associatedprocessing circuitry) may send a control signal (an interrupt signal asdepicted in FIGS. 1A and 1B) to the frame manager 107 and the systemprocessor 108 causing each component to wake up or otherwise be enabled,as described above. Upon receiving the control signal, the frame manager107 is enabled and receives, via an image bus (also depicted in FIGS. 1Aand 1B), the image frames captured by the image sensor 112. Further,upon receiving the control signal, the system processor 108 transitionsto a high-power state (wakes up). During this transition time (t₂), theframe manager 107 continues to buffer image frames captured by the imagesensor 112. Upon waking up at the beginning of time interval t₃, thesystem processor 108 initializes image processing software 109. Duringthis initialization time (t₃), the frame manager 107 continues to bufferimage frames captured by the image sensor 112.

As stated above, exposure levels of the image frames captured by theimage sensor 112 and buffered by the frame manager 107 during the systemprocessor wake-up time t₂ and the image processing softwareinitialization time t₃ may already be optimized for viewing. However,these image frames may need additional processing (e.g., white balanceadjustments). As such, while the image processing software 109 is beinginitialized, the image processing software 109 may configure additionalimage settings (e.g., white balance levels), during the initializationdelay t₃, using one or more of the image frames stored by the framemanager 107 as a reference. As a result, when the image processingsoftware 109 is initialized at the beginning of time interval t₄, thesystem processor 108 may process the image frames stored by the framemanager 107 (e.g., by applying the adjusted white balance levels). Thesystem processor 108 may provide the processed image frames forstreaming while the camera device 102 is in the stream operation mode206.

As a result of the buffering of image frames by the frame manager 107,latencies introduced by the power-up delay of the system processor 108(t₂) and the initialization delay of the image processing software 109(t₃) do not cause any delays in the capture of image frames by the imagesensor 112. Further, use of a fast-boot image processor 112 incombination with the buffering of image frames by the frame manager 107enables the near instantaneous recording of video clips triggered bydetection of an event (e.g., motion), despite any power-up latenciesintroduced by high-power components that are in a low-power state at thetime the event was detected.

FIG. 5 is a flow diagram of an event detection process 500 using a BVRtechnique in accordance with some implementations. The process 500 isoptionally governed by instructions that are stored in a computer memoryor non-transitory computer-readable storage medium (e.g., memory 106 inFIG. 1 ) and that are executed by one or more processors of the cameradevice 102 (e.g., system processor 108). The computer-readable storagemedium may include a magnetic or optical disk storage device, solidstate storage devices such as Flash memory, or other non-volatile memorydevice or devices. The instructions stored on the computer-readablestorage medium may include one or more of: source code, assemblylanguage code, object code, or other instruction format that isinterpreted by one or more processors. Some operations in the process500 may be combined and/or the order of some operations may be changed.

The camera device 102 performs (502) event monitoring using either animage sensor 112 in a low-resolution motion detection mode (502 a), alow-power motion sensor (e.g., a PIR motion sensor as part of eventdetection circuitry 114) (502 b), and/or a low-power audio sensor (e.g.,a microphone as part of event detection circuitry 114) (502 c), asdescribed above with reference to the monitor operation mode 202 duringtime interval t₀.

Upon detection (504) of an event (e.g., motion), the image sensor 112transitions to a high-power (full resolution) image capture mode (506)(or the additional circuitry 114 transmits an interrupt signal to theimage sensor 112 to enable the high-power image capture mode). The imagesensor 112 or the event detection circuitry 114 transmits an interruptsignal to the frame manager 107 to enable the frame manager 107 forbuffering image data recorded by the image sensor 112 (508). The framemanager 107 proceeds to buffer the image data recorded by the imagesensor 112. The image sensor 112 or the event detection circuitry 114also transmits an interrupt signal to the system processor 108 to causethe system processor 108 to transition to a high-power state (wake up)(510). Operations 506, 508, and 510 may be executed in parallel orsubstantially in parallel (e.g., within a time period that is shorterthan the frame rate of the image sensor 112) as described above withreference to the buffer operation mode 204 during time interval t₂.

The system processor 108 (upon waking up) initializes the imageprocessing software 109 (512) as described above with reference to thebuffer operation mode 204 during time interval t₃. During this time, theimage processor 112 continues to capture image data and the framemanager 107 continues to buffer the captured image data.

When the image processing software 109 is initialized, the systemprocessor 108 performs image processing using the initialized imageprocessing software 109 on the image data buffered by the frame manager107 (514). The system processor 108 proceeds to stream the processedimage data to a server system 130 or to a mobile device 140 (516).Operations 514 and 516 may be executed as described above with referenceto the stream operation mode 206 during time interval t₄.

Each of the operations 502-510 may be executed while the systemprocessor 108 is in a low-power standby mode (and/or waking from thelow-power standby mode), while operations 512-516 may be executed whilethe system processor 108 is in a full-power operational mode.Optionally, during the time interval to, the image processor 112 andframe manager 508 may be enabled to capture and store low-resolutionimages prior to an event being detected (503). These low-resolutionimages may be stored in a circular buffer having a predetermined size.For example, the frame manager 107 may be configured to store 5 secondsof video data comprising low-resolution image frames captured prior toan event detection (before time interval t₀). As a result, in someimplementations, the last 5 seconds of video data that occurred justbefore an event was detected may be added to the video clip associatedwith that event. The low-resolution image data stored by the framemanager 107 prior to the detection of an event may be referred to aspre-roll video data. The pre-roll video data may continuously beoverwritten with successively captured pre-roll video data until anevent is detected. Since the pre-roll video data is captured while theimage sensor 112 is in a low-power state, the pre-roll video data maysubject to intermediate processing (e.g., monotone filtering) in orderto optimize the video data for viewing.

In some implementations, the system processor 108 (using the imageprocessing software 109) may determine whether to stream the processedimage data in operation 516 in accordance with one or moreuser-configured thresholds. These thresholds may be configured in orderto further extend battery life of the camera device 102. For example, auser may determine that detected events associated with a length of timeor an amount of motion below a respective threshold or characterized ina particular way (e.g., not associated with a recognized person orobject) should not be streamed. In such a scenario, the system processor108 could be powered back down to a low-power standby mode, and thecommunication circuitry 110 could remain in a low-power standby mode,thus allowing the camera device 102 to consume less power. A user couldadjust motion, time, and recognition sensitivities by settingcorresponding thresholds in, for example, an application executing onthe mobile device 140.

The foregoing description has been described with reference to specificimplementations. However, the illustrative discussions above are notintended to be exhaustive or to limit the claims to the precise formsdisclosed. Many variations are possible in view of the above teachings.The implementations were chosen and described to best explain principlesof operation and practical applications, to thereby enable othersskilled in the art.

The various drawings illustrate a number of elements in a particularorder. However, elements that are not order dependent may be reorderedand other elements may be combined or separated. While some reorderingor other groupings are specifically mentioned, others will be obvious tothose of ordinary skill in the art, so the ordering and groupingspresented herein are not an exhaustive list of alternatives.

As used herein: the singular forms “a”, “an,” and “the” include theplural forms as well, unless the context clearly indicates otherwise;the term “and/or” encompasses all possible combinations of one or moreof the associated listed items; the terms “first,” “second,” etc. areonly used to distinguish one element from another and do not limit theelements themselves; the term “if’ may be construed to mean “when,”“upon,” “in response to,” or “in accordance with,” depending on thecontext; and the terms “include,” “including,” “comprise,” and“comprising” specify particular features or operations but do notpreclude additional features or operations.

What is claimed is:
 1. A method comprising: detecting, while operating asystem processor of a camera device in a standby mode, an event within asensing region of a camera device; causing, responsive to detecting theevent, the system processor to transition from the standby mode to afull-power mode; enabling, responsive to detecting the event, a framebuffer to store image frames captured by an image sensor of the cameradevice; capturing a plurality of image frames associated with at leastportions of the sensing region via the image sensor of the cameradevice; storing, responsive to enabling the frame buffer, the pluralityof image frames; processing, while operating in the full-power mode, theplurality of image frames stored in the frame buffer via the systemprocessor; and providing, responsive to the processing, the processedimage frames for streaming.
 2. The method of claim 1, wherein detectingthe event within the sensing region of the camera device comprisesdetecting one or more motion events or sound events.
 3. The method ofclaim 2, wherein the sensing region comprises an environment surroundingthe camera device within which one or more sensors of the camera deviceare configured to detect the one or more motion events or sound events.4. The method of claim 3, wherein the one or more sensors comprise theimage sensor, wherein detecting the event comprises detecting a motionevent of the one or more motion events via the image sensor while theimage sensor is operating in a low-power motion detection mode, andwherein capturing the plurality of image frames comprises transitioningthe image sensor from the low-power image detection mode to a high-powerimage capture mode in response to detecting the motion event.
 5. Themethod of claim 3, wherein the one or more sensors comprise a passiveinfrared motion sensor, wherein detecting the event comprises detectinga motion event of the one or more motion events via the passive infraredmotion sensor while the image sensor is operating in a standby mode, andwherein capturing the plurality of image frames comprises transitioningthe image sensor from the standby mode to a high-power image capturemode in response to detecting the motion event.
 6. The method of claim3, wherein the one or more sensors comprise an audio sensor, whereindetecting the event comprises detecting a sound event of the one or moresound events via the audio sensor while the image sensor is operating inat least one of a standby mode or a low-power motion detection mode, andwherein capturing the plurality of image frames comprises transitioningthe image sensor from the standby mode or the low-power image detectionmode to a high-power image capture mode in response to detecting thesound event.
 7. The method of claim 1, further comprising: adjusting,while operating the system processor in the standby mode, an exposuresetting of the image sensor while the image sensor is in a low-powermotion detection mode prior to detecting the event, and whereincapturing the plurality of image frames comprises transitioning theimage sensor from the low-power motion detection mode to a full-powerimage capture mode using the adjusted exposure setting.
 8. The method ofclaim 1, wherein causing the system processor to transition from thestandby mode to the full-power mode is performed during a first timeperiod, and wherein the plurality of image frames includes one or moreimage frames captured and stored frames during the first time period. 9.A camera device comprising: an image sensor; a frame buffer; a systemprocessor; and memory storing one or more programs to be executed by thesystem processor, the one or more programs including instructions for:detecting, while operating a system processor of a camera device in astandby mode, an event within a sensing region of a camera device, theevent including one or more motion events or sound events; causing,responsive to detecting the event, the system processor to transitionfrom the standby mode to a full-power mode; enabling, responsive todetecting the event, a frame buffer to store image frames captured by animage sensor of the camera device; capturing a plurality of image framesassociated with at least portions of the sensing region via the imagesensor of the camera device; storing, responsive to enabling the framebuffer, the plurality of image frames; processing, while operating inthe full-power mode, the plurality of image frames stored in the framebuffer via the system processor; and providing, responsive to theprocessing, the processed image frames for streaming.
 10. The cameradevice of claim 9, wherein the instructions further include instructionsfor: detecting a motion event of the one or more motion events using theimage sensor while the image sensor is operating in a low-power motiondetection mode.
 11. The camera device of claim 9, further comprising: atleast one of a passive infrared motion sensor or an audio sensor, andwherein the instructions for detecting the event include instructionsfor detecting a motion event of the one or more motion events via thepassive infrared motion sensor or detecting a sound event of the one ormore sound events via the audio sensor.
 12. The camera device of claim9, wherein the instructions further include instructions for: adjusting,while operating the system processor in the standby mode, an exposuresetting of the image sensor while the image sensor is in a low-powermotion detection mode prior to detecting the event; and transitioningthe image sensor from the low-power motion detection mode to afull-power image capture mode sufficient to enable the image sensor tocapture the plurality of image frames using the adjusted exposuresetting.
 13. The camera device of claim 9, wherein the instructionsfurther include instructions for: causing the system processor toperform the transition from the standby mode to the full-power modeduring a first time period; and capturing and storing image framesduring the first time period.
 14. The camera device of claim 9, whereinthe instructions further include instructions for: initializing, priorto processing the plurality of image frames, image processing softwareduring a first time period; and capturing and storing image framesduring the first time period.
 15. A non-transitory computer-readablestorage medium storing one or more programs configured for execution bya camera device, the one or more programs including instructions for:detecting, while operating a system processor of a camera device in astandby mode, an event within a sensing region of a camera device, theevent including one or more motion events or sound events; causing,responsive to detecting the event, the system processor to transitionfrom the standby mode to a full-power mode; enabling, responsive todetecting the event, a frame buffer to store image frames captured by animage sensor of the camera device; capturing a plurality of image framesassociated with at least portions of the sensing region via the imagesensor of the camera device; storing, responsive to enabling the framebuffer, the plurality of image frames; processing, while operating inthe full-power mode, the plurality of image frames stored in the framebuffer via the system processor; and providing, responsive to theprocessing, the processed image frames for streaming.
 16. Thenon-transitory computer-readable storage medium of claim 15, wherein theinstruction further include instructions for: detecting a motion eventof the one or more motion events using the image sensor while the imagesensor is operating in a low-power motion detection mode; andtransitioning the image sensor from the low-power motion detection modeto a full-power image capture mode in response to detecting the motionevent.
 17. The non-transitory computer-readable storage medium of claim15, wherein the instructions further include instructions for: detectinga motion event of the one or more motion events via a passive infraredmotion sensor of the camera device while the image sensor is operatingin a low-power motion detection mode; and transitioning the image sensorfrom the low-power motion detection mode to a full-power image capturemode in response to detecting the motion event.
 18. The non-transitorycomputer-readable storage medium of claim 15, wherein the instructionsfurther include instructions for: detecting a sound event of the one ormore sound events via an audio sensor of the camera device while theimage sensor is operating in at least one of a standby mode or alow-power motion detection mode; and transitioning the image sensor fromthe standby mode or the low-power motion detection mode to a full-powerimage capture mode in response to detecting the sound event.
 19. Thenon-transitory computer-readable storage medium of claim 15, wherein theinstructions further include instructions for: adjusting, whileoperating the system processor in the standby mode, an exposure settingof the image sensor while the image sensor is in a low-power motiondetection mode prior to detecting the event; and transitioning the imagesensor from the low-power motion detection mode to a full-power imagecapture mode using the adjusted exposure setting.
 20. The non-transitorycomputer-readable storage medium of claim 15, wherein the instructionsfurther include instructions for: causing the system processor toperform the transition during a first time period; and capturing andstoring image frames during the first time period.